Damped flexure mounts for use in web winding

ABSTRACT

In a machine for continuously winding a web onto a wind-up roll having at least a lay-on roll in contact with the surface of the wind-up roll and a spreader roll ahead of the lay-on roll, the improvement wherein the lay-on roll and the spreader roll are mounted within a frame by damped flexure mounts supporting the ends of the rolls and attached by resilient attachments. The flexural mounts have a plurality of alternating spring steel leaves and leaves of polymeric material.

United States Patent [1 1 [111 3,912,188 Ballard Oct. 14, 1975 [54]DAMPED FLEXURE MOUNTS FOR USE IN 1,419,049 6/1922 Harsel 242/752 WEBWINDING 2,267,107 12/1941 .luillard 242/753 3,048,346 8/1962 Karber242/753 [75] Inventor: .Raymond Marvin Ballard, 3,670,980 6/1972 Mukal242/752 X Midlothian, Va.

[73] Assignee: E. I. Du Pont de Nemours and Primary ExaminerEdward J.McCarthy Company, Wilmington, Del.

[22] Filed: Aug. 26, 1974 [57] ABSTRACT PP .1 500,496 In a machine forcontinuously winding a web onto a wind-up roll having at least a lay-onroll in contact [52] US. Cl. 242/75.2 with the surface of the wihd'upreh and a Spreader [51] Int. Cl B65h 23/10 ahead of the lay'eh roll theimprovement wherein the [58] Field of Search n 242/752 75.3. 267/36 Rlay-on roll and the spreader roll are mounted within a 267730 41 5 4frame by damped flexure mounts supporting the ends of the rolls andattached by resilient attachments. The [56] References Cited flexuralmounts have a plurality of alternating spring UNITED STATES PATENTS9/1917 Trier 242/752 steel leaves and leaves of polymeric material.

11 Claims, 3 Drawing Figures U.S. Patent Oct. 14, 1975 Sheet 1 of23,912,188

US. Patent Oct.14,1975 sheetzofz 3,912,188

DAMPED FLEXURE MOUNTS FOR USE IN WEB WINDING BACKGROUND OF THE INVENTIONThis invention relates to a mounting device, and more particularly to aflexible mounting device having improved damping properties.

In certain manufacturing processes, e.g., the production of films, wherethe end product or any intermediate thereof is a web of material thereis a need for improving the method by which handling and winding of thewebs onto rolls is accomplished. A typical web winding apparatuscomprises a plurality of rolls arranged to guide the web onto -a windingroll. Where thin flexible webs are continuously wound at high speeds thewinding system becomes very critical and sensitive to variations in webtension and other disturbances caused by rolls having eccentric cores.

Of particular concern where webs are produced on rolls in their finishedform is the elimination of transverse direction wrinkles and machinedirection ridges which may result in permanent distortion of the webmaterial. The transverse direction wrinkles are convolutions in thetransverse direction which occur in the interior of a wound roll and arecaused by low mean tension levels and high tension peaks in the webduring winding and by an excessive amount of air that is wound-in 38during windup.

Machine direction ridges are circumferential ridges occurring throughouta roll and are caused, in particular, by high web tension levels and alack of lateral web mobility during winding. No web tension level isknown to exist where neither problem occurs.

The prior art has recognized some of the problems involved in windingwebs of material. US. Pat. No. 3,329,368 to Mastriani, for example,discloses an improvement in a web winding machine for automaticallyadjusting the position of the axis of a rewind roll relative to theposition of a lay-on roll, responsive to variations in diameter of therewind roll. The lay-on roll is disposed in intermediate engagement witha platen and rewind roll by means of a spring plate and connecting link.This arrangement appears to improve web handling where there exists nounsupported web by allowing the lay-on roll to adjust to changes indiameter of the rewind roll while exerting constant pressure.

DESCRIPTION OF THE INVENTION It has been found that transverse directionwrinkles and machine direction ridges can be substantially eliminated inaccordance with the present invention which is particularly pointed outin the appended claims and is illustrated in a preferred embodiment inthe accompanying drawings wherein:

FIG. 1 is a perspective view ofa web winding apparatus incorporatingflexure mounting devices of the present invention.

FIG. 2 is a right end view of the apparatus of FIG. 1 taken along line22.

FIG. 3 is an enlarged, detailed elevational view of a flexure mountingdevice in accordance with the present invention.

Referring now to FIGS. 1 and 2, a web of material such as polymeric filmis wound onto a winding roll 11. A pivot roll 12, a spreader roll 13 anda lay-on roll 14 are arranged in essentially parallel relation towinding roll 11 by means ofa frame 15 comprising support arms l6 and 17which are attached to a pivot shaft I8 at points 19 and 20,respectively. Air cylinders 21 are used to lift the frame assembly 15and provide friction damping for the pivoted support arms 16 and 17.

During the winding process lay-on roll 14 remains in contact with thesurface of winding roll 11 at 22. Uniform constant pressure contact at22 must exist between the lay-on roll 14 and the winding roll 11 tomaintain a constant minimum thickness air layer that is wound-in.Surface irregularities in winding roll 11 may produce a bouncing contactbetween lay-on roll 14 and winding roll 11. Friction damping is providedto overcome said bouncing contact by means of damped flexure mounts 23in accordance with the present invention. Friction damping provides asmoother more effective control than viscous damping for low velocitiesand small displacements involved in bouncing contact.

A spreader roll 13 (such as a Flex-Spreader" roll manufactured by theSamuel Bingham Company) is located immediately ahead of the lay-on roll14. It is attached to support arms 16 and 17 by means of clamped flexuremounts 24 aligned parallel to the web 10 approaching the roll topreclude web tracking problems. The spreader roll 13 tenters (i.e.,provides transverse direction tension to the incoming web 10 by theaction of helical-conical grooves provided in the soft rubber rollsurface. Machine direction tension produces transverse direction tensilestress in the web 10 by the outward resilient movement of the conicalelements of the roll. When a web 10 is wound on a winding roll having aneccentric core, a sinusoidal tension variation is induced. In apreferred embodiment of the present invention damped flexure mounts 23and 24 (enlarged, detailed views of which are shown in FIG. 3) providefor relative motion between lay-on roll 14 and spreader roll 13 therebycreating a desired accumulator effect to attenuate web tensionvariations.

Counterweights 25 are employed to establish the desired force, i.e., nippressure, between lay-on roll 14 and winding roll 11. In a preferredembodiment damped flexure mounts 26 are used to mount saidcounterweights 25 to an extension of support arms 16 and 17 thereby toreduce the dynamic inertia, i.e., impedance, of the pivoted supportframe 15. Optionally, the counterweights 25 can be attached to pivotshaft 18 by means of a damped flexure mount 26 and cantilever beammember 27.

Referring now to FIG. 3 (which illustrates in an enlarged, detailed viewthe flexure mounts 23 and 24 and how they are associated with rolls 14and 13, respectively) the damped flexure mount 50 of the presentinvention consists essentially of a plurality of alternating springsteel leaves 51 and leaves of polymeric material 52 rigidly fastened atone end by any suitable means 53. In a preferred embodiment thefastening means is adapted to be rigidly mounted on the support arms 16and 17 of frame 15. The opposite end of the flexure mount 54 is adaptedto fasten to the ends 55 of a web handling roll 58 by means of resilientattachments 56. In a preferred embodiment said resilient attachments 56comprise a plurality of resilient washers such as Belleville springwashers arranged alternately and assembled with any suitable machinefastener 57.

The alternating spring steel leaves 51 can be formed of any suitablegrade steel with AISI 1070 or AISI 4130 heat treated steel beingpreferred.

In a preferred embodiment the polymeric leaves 52 consist essentially ofa polyacetal resin having a static coefficient of friction in the rangeof about 0.15 to 0.3. The dynamic coefficient of friction ranges betweenabout 0.18 and 0.33. Asbestos-phenolic compositions can also be used forthe polymeric leaves 52.

When the flexure mount of the present invention is ready for use, theload imposed on the resilient washers 56 by the fastener 57, which canbe a typical machine bolt, is adjusted to achieve the critical dampingrequired of the web carrying roll 58. In a particularly preferredembodiment of this invention in the use of damped flexure mountswith webhandling machines, the polymeric leaf material is selected to have alower static coefficient of friction than dynamic coefficient offriction (e.g., a difference of about 0.02 to 0.05) thereby precluding aslip-stick phenomenon.

The damped flexure mount of the instant invention provides an improvedand simple method of attenuating tension variations in web handlingmachines. Disturbances in the winding process that would normally causeweb elongations and consequent induced tension variations are absorbedby changes in length of the web span between the lay-on roll 14 andspreader roll 15 because of their capability to move relative to oneanother. The multiple uses of damped flexure mounts for roll andcounterweight mounting provides a low inertia, high compliance system.

I claim:

1. In a machine for continuously winding a web onto a wind-up rollcomprising a lay-on roll in contact with the surface of the wind-uproll, the improvement wherein said lay-on roll is mounted within a frameby damped flexure mounts supporting the ends of said layon roll one endof said flexure mounts being attached to said frame and the other endbeing attached to the ends of said roll by resilient attachments, saidflexure mounts having a plurality of alternating spring steel leaves andleaves of polymeric material.

2. A machine as defined in claim 1 wherein said frame has a spreaderroll mounted thereon by damped flexure mounts supporting the ends ofsaid spreader roll one end of said flexure mounts being attached to saidframe and the other end being attached to the ends of said rollby'resilient attachments, said spreader roll positioned to permit saidweb to pass thereover prior to passing around said lay-on roll.

3. A machine as defined in claim 2 wherein said spreader roll and saidlay-on roll move relative to one another by means of damped flexturemounts thereby creating an accumulator effect to attenuate web tensionvariations when winding a web of material, portions thereof beingunsupported.

4. A machine as defined in claim 2 wherein said frame comprises at leasttwo support arms each having a counterweight suspended therefrom bymeans of a damped flexure mount one end of said flexure mount beingattached to said arm and the other end being attached to saidcounterweight by resilient attachments thereby to establish the desirednip pressure between said lay-on roll and said wind-up roll.

5. A machine as defined in claim 4 wherein said resilient attachmentscomprise a plurality of resilient washers. I

6. A machine as defined in claim 4 wherein said polymeric material has astatic coefficient of friction within the range of about 0.15 to 0.3 anda dynamic coefficent of friction with the range of about 0.18 to 0.33,said static coefficient being lower than said dynamic coefficient.

7. A machine as defined in claim 6 wherein the polymeric material is apolyacetal resin or an asbestos containing phenolic resin.

8. A damped flexure mounting device for mounting web handling rolls on aframe comprising a plurality of alternating spring steel leaves andleaves of polymeric material, and resilient attaching means forattaching one end of said flexure mounting device to the ends of suchrolls i 9. A flexure mounting device as described in claim 8 whereinsaid resilientattaching means comprise a plurality of resilient washers.7

10. A flexure mounting device as defined in claim 9 wherein saidpolymeric material has a static coefficient of friction within the rangeof about 0.15 to 0.3 and a dynamic coefficient of v friction within therange of about 0.18 to 0.33, said static coefficient being lower thansaid dynamic coefficient.

11. A flexure mounting device as defined in claim 10 wherein thepolymeric material is a polyacetal resin or an asbestos containingphenolic resin.

1. In a machine for continuously winding a web onto a wind-up rollcomprising a lay-on roll in contact with the surface of the wind-uproll, the improvement wherein said lay-on roll is mounted within a frameby damped flexure mounts supporting the ends of said lay-on roll , oneend of said flexure mounts being attached to said frame and the otherend being attached to the ends of said roll by resilient attachments,said flexure mounts having a plurality of alternating spring steelleaves and leaves of polymeric material.
 2. A machine as defined inclaim 1 wherein said frame has a spreader roll mounted thereon by dampedflexure mounts supporting the ends of said spreader roll , one end ofsaid flexure mounts being attached to said frame and the other end beingattached to the ends of said roll by resilient attachments, saidspreader roll positioned to permit said web to pass thereover prior topassing around said lay-on roll.
 3. A machine as defined in claim 2wherein said spreader roll and said lay-on roll move relative to oneanother by means of damped flexture mounts thereby creating anaccumulator effect to attenuate web tension variations when winding aweb of material, portions thereof being unsupported.
 4. A machine asdefined in claim 2 wherein said frame comprises at least two supportarms each having a counterweight suspended therefrom by means of adamped flexure mount , one end of said flexure mount being attached tosaid arm and the other end being attached to said counterweight byresilient attachments thereby to establish the desired nip pressurebetween said lay-on roll and said wind-up roll.
 5. A machine as definedin claim 4 wherein said resilient attachments comprise a plurality ofresilient washers.
 6. A machine as defined in claim 4 wherein saidpolymeric material has a static coefficient of friction within the rangeof about 0.15 to 0.3 and a dynamic coefficent of friction with the rangeof about 0.18 to 0.33, said static coefficient being lower than saiddynamic coefficient.
 7. A machine as defined in claim 6 wherein thepolymeric material is a polyacetal resin or an asbestos containingphenolic resin.
 8. A damped flexure mounting device for mounting webhandling rolls on a frame comprising a plurality of alternating springsteel leaves and leaves of polymeric material, and resilient attachingmeans for attaching one end of said flexure mounting device to the endsof such rolls .
 9. A flexure mounting device as described in claim 8wherein said resilient attaching means comprise a plurality of resilientwashers.
 10. A flexure mounting device as defined in claim 9 whereinsaid polymeric material has a static coefficient of friction within therange of about 0.15 to 0.3 and a dynamic coeFficient of friction withinthe range of about 0.18 to 0.33, said static coefficient being lowerthan said dynamic coefficient.
 11. A flexure mounting device as definedin claim 10 wherein the polymeric material is a polyacetal resin or anasbestos containing phenolic resin.